This invention relates to the identification of the source of a corona discharge in apparatus under test.
Underwater repeatered telephone cable systems are series powered by high voltage dc power supplies established at the shore terminals. Each repeater and equalizer that is utilized in such a system contains a power separator filter for extracting the dc current from the center conductor of the coaxial cable while allowing signal transmission. Corona discharges which can interrupt signal transmission can occur across the dielectrics of the high voltage filter capacitors within the underwater repeaters and equalizers. These discharges are often the result of a contamination on the capacitor insulating container or within the capacitor dielectric. Since underwater repeaters and equalizers are difficult to service once installed, it is desirable to identify a faulty repeater or equalizer before it is put into service. Furthermore, it is desirable to identify, with certainty, the particular faulty component(s) which is likely to cause corona discharge within a repeater or equalizer so it may be either repaired or replaced. Repeaters and equalizers are thus corona discharge tested before being placed into service. Prior art corona discharge testers, however, could only identify that a particular repeater or equalizer under test was subject to corona discharges and were not capable of identifying the particular faulty component within. Therefore, once a repeater or equalizer was determined to be faulty, the entire network had to be laboriously examined to find the discharge producing component.